This application claims the priority of Germany Patent Document 199 48 037.0, filed Oct. 6, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an electric plug connecting element and system.
In a conventional electric plug connecting element a separate contact member, with which a connection to a contacting point of a complementary plug connecting element can be made, is usually fastened to the stripped end of an electric line. The cable end and the separate contact member are enclosed by a plug housing in order to provide insulation, protection improved handling and to guarantee a reliable and repeatable connection. Frequently the line with its attached contact member floats in the plug housing.
This customary plug construction generates additional costs due to the production and attachment of a separate contact member to the cable end. Moreover, the additional contact parts result in a weight increase of the entire plug connection.
When using an antenna or coaxial cable, it is known to use the conductor of a cable directly as the contact element. In so doing, the insulation on the end of the cable is removed. When fitting together into a socket, the end of the conductor is inserted into a receptacle. To fasten the coaxial cable to another cable or device, a nut, forming one part of the plug connection, is screwed on a housing member of the other cable or the device socket that exhibits an external thread. However, this embodiment can be used only for static applications. For use in an area where there are vibrations and oscillations, it is inappropriate.
German Patent DE 39 15 611 C1 discloses an electric plug connection, where a receptacle member exhibits a plug slit with resilient contact noses. A related plug member exhibits a plug leg with a borehole, through which a cable conductor serving as the contact member is inserted. When fitting together the plug connection, the resilient contact noses are forced apart during insertion into the plug slit, thus dragging the contact member along the contact noses. Thus, the conducting surface of the contact member can be damaged.
German Patent DE 195 00 288 A1 describes an indicating device with an electric contact which extends outward and is able to be removably connected to a counter contact. It is possible to fit together the indicating device and the counter contact element owing to a moveable configuration of the contact or the counter contact and movement of the same over a lever system. However, the presence of vibration may have a negative effect on the contacting and result in a subsequent malfunction.
The object of the invention is to improve an electric plug connecting element and system in such a manner that a simple and inexpensive reliable electric connection of an electric cable is also possible in areas where vibrations and oscillations occur.
The concept of the invention constitutes the direct use of the stripped ends of the conductors of a cable, held in a housing, as the contact elements. In so doing, these conductors are brought directly into contact with the assigned contact elements of a complementary plug connecting element. These measures dispense with a separate contact member, to be adjoined to the conductor. Thus, not only the production of such a contact member but also the process step of providing such a separate contact member at the end of a line can be dispensed with.
The ends of the conductors are accommodated or embedded in the housing in such a manner that a motionless connection is possible between the ends of the conductors and the assigned contact elements of a complementary plug connecting element when connected to the complementary plug connecting element. In particular the connection is also gas tight.
The ends of the conductors can be positioned both close to a housing internal member and to the assigned contact elements of the complementary plug connecting element. With this arrangement the ends of the conductors are pressed together when the electric plug connecting element is joined together with its complementary element so that the result is not only a gas-free but also a motion-free electrical connection between the electrically conducting elements of both plug connecting elements. Thus, the reliability of the plug connection is also guaranteed in areas of application, where oscillations, vibrations or their forces affecting the electrical connection occur.
Furthermore, the housing with the stripped ends of the conductors is designed in such a manner that, when fitting together with the complementary plug connecting element, an essentially frictionless contact, without any plug-in force, is possible. This measure serves especially to avoid surface damage when fitting together the two conducting parts that serve as the contact elements. If the ends of the conductors and the contact elements of a complementary plug connecting element lie one above the other when fitting together both plug connecting elements, then they rub against each other, thus possibly damaging or impairing the surface of the various conductors. This situation can be prevented in the conventional manner by treating the surface with a frictionless material, like gold. To avoid such an expensive surface treatment, the electrical plug connecting elements, especially the housings, which are to be fitted together, can be designed in such a manner that the ends of the conductors and the contact elements do not touch in the first step of the fitting together operation. After essentially completing the fitting together operation of the two housings, the related ends of the conductors and the contact elements ought to be brought into contact with each other without sliding friction and into their end position by another relative motion of the housings. In so doing, the additional relative motion can include swivelling, twisting, tilting or a combination of these motions.
A preferred embodiment of the invention is characterized by the fact that the ends of the conductors are shaped and/or surface treated. For example, for use of multicore strands it is possible to tin coat or to treat the surfaces in some other manner so that a suitable contact element with a good transition resistance can be created out of the conductor. In so doing, the surface treatment also serves to protect the ends of the line.
In addition, it is possible to process the shape of the ends of the conductors. For example, they can be bent or deformed in another defined manner. Therefore, larger adjoining areas between the ends of the conductors and the contact elements of the complementary plug connecting element can be created. Additionally, it is possible to provide optimal shapes for fitting together the electric plug connecting element of the invention, on the one hand, and the complementary plug connecting element, on the other hand. Naturally both aforementioned kinds of treatment can also be combined. For example, the ends of the conductors can be tin coated and subsequently shaped or deformed.
It is also advantageous for the two housing members to be held in their end position with a locking connection. In this respect it is necessary to provide a locking element on the housing of the electrical plug connecting element. This locking element acts together with a counter element on the complementary plug connecting element.
According to a another embodiment, the housing is molded or cast on the cable and is made preferably of a plastic material.
In the design of both the housing of the electric plug connecting element as well as that of the complementary plug connecting element there is, in essence, a high degree of design freedom. Thus, the housings can be constructed in such a manner that the two housings of the plug connecting elements are connected together by relative rotation. As an alternative, the two housings can be fitted together, first, by linear displacement and then brought into a final position by an opposing swivel motion, after which the contacts of the electrical plug connecting elements lie one above the other. It is an essential feature of the invention that the ends of the conductors serve directly as the contact elements for making direct contact with the assigned contact elements of the complementary plug connecting element.
Naturally the complementary plug connecting element can also be designed so that the contact elements are formed by the conductors themselves.